By Colum LynchColum Lynch is Foreign Policy's award-winning U.N.-based senior diplomatic reporter. Lynch previously wrote Foreign Policy's Turtle Bay blog, for which he was awarded the 2011 National Magazine Award for best reporting in digital media.

An effort by the Obama administration to reinforce the powers of U.N. chemical weapons inspectors in Syria Wednesday evening foundered in the face of Russian and Chinese opposition in the U.N. Security Council, according to council diplomats.

Seizing on rebel claims that Syrian authorities massacred hundreds of civilians by firing chemically-laced rockets onto a Damascus suburb, the United States joined Britain and France in calling for an emergency session of the U.N. Security Council to rally international support for an investigation into the incident. The three Western powers also wrote a letter to U.N. Secretary General Ban Ki-moon, signed by 32 other governments, calling for an urgent investigation. But the efforts failed to result in anything other than a tepid statement from the Security Council thanks to some final edits by the Russians and Chinese.

The Obama administration’s goal was to have a U.N. chemical weapons team, which was already in Syria to investigate other chemical weapons allegations, launch a probe into the new allegations. That team, headed by Swedish scientist Ake Sellstrom, arrived in Damascus on Sunday.

The United States, which was represented by the second highest-ranking American official at the United Nations, Ambassador Rosemary Di Carlo, circulated a draft resolution, which was obtained by Foreign Policy, that called on U.N. Secretary General Ban Ki-moon to "urgently take the steps necessary for today’s attack to be investigated by the U.N. mission on the ground." But it also would have applied pressure on Syrian President Bashar al-Assad to grant the inspectors greater latitude. The draft would have called on all combatants in Syria to "allow safe, full and unfettered access to the U.N. mission and to comply with all requests for evidence and information. " It also would have underscored the "importance of a fully independent and impartial [investigation] into all allegations of chemical weapons use in Syria."

In the end, the most strenuous provisions of the American draft were stripped out during closed-door negotiations with Russia and China. Instead, the 15-nation council issued a milder statement that made no reference to today’s alleged chemical weapons attack. The council merely expressed "a strong concern" about "the allegations [of chemical weapons use] and the general sense there must be clarity on what happened." The statement also did little to strengthen the inspector’s mandate, but simply "welcomed the determination of the [U.N.] secretary general to ensure a thorough, impartial and prompt investigation."

Clearly miffed, National Security Advisor Susan Rice took to Twitter to declare that the "Syrian government must allow the UN access to the attack site to investigate. Those responsible will be held accountable."

That sentiment was also echoed by U.N. Deputy Secretary General Jan Eliasson, whotold reporters after Security Council consultations that "we see the need to investigate this as soon as possible." He added that "We are in contact with the Syrian Government. We hope that all other parties will cooperate." But as long as Russia and China are watering down Security Council statements, Syria’s cooperation appears unlikely.